Web drying apparatus



y 3, 1967 N. MJREITZEL WEB DRYING APPARATUS 2 Sheets-Sheet 1 Filed Feb.12, 1965 23, 1967 N. M. REITZEL 3,320,677

WEB DRYING APPARATUS Filed Feb. 12, 1965 2 Sheets-Sheet 2 United StatesPatent 3,320,677 WEB DRYING APPARATUS Nicolas M. Reitzel, Boylston,Mass., assignor to Rice Barton Corporation, Worcester, Mass, acorporation of Massachusetts Filed Feb. 12, 1965, Ser. No. 432,103 12Claims. (Cl. 3454) This invention relates to web drying apparatus.

The basic object of the invention is to provide apparatus, simple andpractical both to manufacture and to use, for controlling the profile(i.e., liquid content plotted against width) of Webs being dried.

In one important aspect, the invention features provision, between amultiplicity of pair of dryer rolls, of a corresponding multiplicity oftransversely extending plenums each providing at least threetransversely consecutive outlet areas through which drying gas may beblown out under different pressures in central and side areas through afelt, moving over the dryer rolls and felt rolls, into the open-sidedpocket defined by the felt, the web, and a dryer roll, some of the areasbeing of different (transverse) widths, in different plenums andotherwise. In another important aspect, the invention features providingplenums with compartments inwhich transversely consecutive outlet endzones are in communication with vertically consecutive zones extendingtransversely to a side of the dryer, in which at the side are placed atleast in the two outermost compartments flow controllers for varyingpressure at the outlet ends. Other important novel features of preferredembodiments are grooved felt rolls cooperatively associated with theplenums, provision in each plenum of three compartments, master controlspermitting simultaneous varying of a multiplicity of the flowcontrollers, and in association with at least one dryer, a high velocitydrying hood.

Other objects, features and advantages will appear from the followingdescription of a preferred embodiment of the invention, taken with theattached drawings thereof, in which:

FIG. 1 is a diagrammatic view of the dry end of a paper machine;

FIG. 2 is a sectional view at 22 of FIG. 1;

FIG. 3 is a sectional view at 33 of FIG. 1;

FIG. 4 is a sectional view at 4'4 of FIG. 1;

FIG. 5 is a sectional view at 55' of FIG. 1;

FIG. 6 is a sectional view at 6-6 of FIG. 2; and

FIG. 7 is an isometric diagram of the flow controls.

Referring now more particularly to the drawings, there is shown in FIG.1 an upper row of dryer rolls 10 and a lower row of dryer rolls 12.Although only ten dryer rolls are shown in each row, a typical actualinstallation would have thirty dryers in each row. Although onlyfourteen plenums (14, 16, 18, 20, and 22) are shown, said typicalinstallation would have forty-eight.

Each plenum is divided into three compartments A, 'B, and C, and eachcompartment extends horizontally from its inlet end and then downwardlyat its outlet end, the compartments being vertically consecutive towardtheir inlet ends, and transversely consecutive at their outlet ends.Each compartment A and C includes a damper 24, 25 toward its inlet endfor varying rate of flow therethrough and pressure therein at the outletend.

The plenums 14 (of which six, three up and three down, would be presentin said actual installation) have side compartments A and C each ofwhich at its outlet end is three-eighths of the width of the plenum,leaving a center compartment B one quarter of said width. The plenums 16(of which six, three up and three down, would also be present in saidactual installation) have side compartments A and C and a centercompartment B all at their outlet ends one-third the width of the plenum16.

The plenums 18 (of which also six would be present in the actualinstallation mentioned, three up and three down), have side compartmentsA and C each onequarter, at their outlet ends, the width of plenum 18,the center compartment B being half said width. The plenums 20 (of whichagain six, three up and three down, would be found in said actualinstallation) have side compartments A and C that at their outlet endsare oneeighth said width, the center compartment B being threequartersof said width. At their inlet ends, all said compartments A, B, and Cextend fully across the plenum, and dampers 24, 25, 26, and 27 aremounted in the uppermost and lowermost compartments A and C toward saidinlet ends to vary flow rate therethrough; all the compartments A, B,and C are supplied from a common source of hot air.

Each plenum includes a housing 28 the lower ends 29 of which extend forshort distances in directions generally tangential to felt rolls 30about which felts 32 are trained. The felt rolls include annular grooves34 through which air blown through the plenums is blown through thefelts all around the rolls 30, as indicated by the arrows in FIG. 6.Extending over the outlet ends of compartments A, B, and C of eachplenum is curved perforated distributor plate 36, for distribution ofair blown through each compartment.

Dampers 24, which regulate flow through the front side compartments A ofthe top row plenums 14, 16, 18, and 20, are regulated for simultaneousmovement as a group by control knob 40. Dampers 25, which regulate flowthrough the back side compartments C of the top row plenums 14, 16, 18,and 20, are regulated for joint movement as a group by control knob 42.Dampers 26, in front side compartments A of the bottom row plenums 14,16, 18, and 20, are similarly regulated by knob 44. Dampers 27, in backside compartments C of said bottom row plenums are thus regulated byknob 46. Each damper suitably has associated with it, an air actuator 47of character well known in the art, all the air actuators for each groupof dampers being controlled by the groups respective knob.

The plenums 22 are constructed identically as are the plenums 16.However, the dampers in the side compartments of the plenums 22 aremanually operable only, for normally setting only on initial machinesetup, operating adjustments in normal use being made through the knobscontrolling the dampers of plenums 14, 16, 18, and 20.

High velocity hood 48 of character well known in the art, has amultiplicity of transverse compartments through which air may be blownat selectively different rates to eliminate small moisture variations,which usually show up as streaks, across the width of the web w.

In operation, despite great simplicity (thus, each plenum in thepreferred embodiment has only three compartments and two dampers, andthe dampers are not only easily accessible for manual control variationbut may be regulated through only four control knobs), great profilecontrol may be maintained. Moisture content in each side of each row ofplenums is separately controllable, for gross moisture variationprevention, and hood 4S cooperatively smooths out small moisturevariation. Because the widths of the side compartments of difierentplenums varies, sharp boundaries are eliminated, and a graduated, shadedeffect is achieved. At the same time, number of compartments and dampersfor each plenum may be minimized, for great simplicity.

What is claimed is:

1. Web drying apparatus for profile control of a web by blowing airthrough a felt into a plurality of longitudinally successive pocketsdefined by said felt, one row of dryer rolls, and said web runningbetween dryer rolls of said one row of dryer rolls and dryer rolls ofanother row of dryer rolls, said apparatus comprising in combinationwith said felt a plurality of longitudinally successive plenurns, eachof said plenums including at least three compartments with transverselyconsecutive outlet portions adjacent said felt having widths in atransverse direction, certain of said widths being ditferent fromcertain others thereof, and flow control elements in both thosecompartments transversely extreme at their outlet portions at least oneof said plenums including a said width different from a correspondinglypositioned said width in another said plenum.

2. The apparatus of claim 1 in which each of said plenums includes twoside compartments and a center compartment.

' 3. The apparatus of claim 2 in which said two side compartmentsinclude outlet portions of the same said width.

4. The apparatus of claim 3 which includes a multiplicity of differentside outlet compartment Widths.

5. The apparatus of claim 4 which includes plenums with four differentarrangements of said widths, one of said arrangements having side outletcompartment widths of /s total outlet width, another having side outletcompartment widths of total outlet width, another having side outletcompartment widths of /3 total outlet width, and another having sideoutlet compartment widths of total outlet width.

6. The apparatus of claim 1 in which said compartments are verticallyconsecutive toward their inlet portions, and said flow control elementsare disposed in said compartments where they are vertically consecutive.

7. The apparatus of claim 1 in which at least one of said compartmentsintermediate of said compartments transversely extreme at their outletportions is free of a.

flow controller.

8. The apparatus of claim 1 in which outlet portions of at least one ofsaid plenums are positioned adjacent a circumferentially grooved feltroll to blow through the grooves and said felt therearound.

9. The apparatus of claim 1 which includes a high velocity dryer hood.

10. The apparatus of claim 1 in which a plurality of said fiow controlelements are jointly controlled by a single control element.

11. The apparatus of claim 4 in which a multiplicity .of said flowcontrol elements for compartments of plenums in one row and with outletportions on one side of said apparatus are jointly controlled by asingle control element.

12. The apparatus of claim 5 in which certain of said I flow controlelements of said side are not jointly controlled with the others.

References Cited by the Examiner UNITED STATES PATENTS FREDERICK L.MATTESON, JR., Primary Examiner.

A. D. HERRMANN, Assistant Examiner;

1. WEB DRYING APPARATUS FOR PROFILE CONTROL OF A WEB BY BLOWING AIRTHROUGH A FELT INTO A PLURALITY OF LONGITUDINALLY SUCCESSIVE POCKETSDEFINED BY SAID FELT, ONE ROW OF DRYER ROLLS, AND SAID WEB RUNNINGBETWEEN DRYER ROLLS OF SAID ONE ROW OF DRYER ROLLS AND DRYER ROLLS OFANOTHER ROW OF DRYER ROLLS, SAID APPARATUS COMPRISING IN COMBINATIONWITH SAID FELT A PLURALITY OF LONGITUDINALLY SUCCESSIVE PLENUMS, EACH OFSAID PLENUMS INCLUDING AT LEAST THREE COMPARTMENTS WITH TRANSVERSELYCONSECUTIVE OUTLET PORTIONS ADJACENT SAID FELT HAVING WIDTHS IN ATRANSVERSE DIRECTION, CERTAIN OF SAID WIDTHS BEING DIFFERENT FROMCERTAIN OTHERS THEREOF, AND FLOW CONTROL ELEMENTS IN BOTH THOSECOMPARTMENTS TRANSVERSELY EXTREME AT THEIR OUTLET PORTIONS AT LEAST ONEOF SAID PLENUMS INCLUDING A SAID WIDTH DIFFERENT FROM A CORRESPONDINGLYPOSITIONED SAID WIDTH IN ANOTHER SAID PLENUM.